Position Sizing for Funded Perp Accounts: Risk Math That Respects a 3% Day
Position sizing funded account math is not about how much leverage the ticket allows. It is about how much of your fixed loss allowance a single idea is allowed to consume. On MyFundedPerps, every plan carries a 3% daily loss limit and a static maximum drawdown measured from your starting balance, so the math is unforgiving in a specific way: your risk budget is a fixed dollar number, not a percentage of whatever equity you happen to have today. This guide walks through the sizing workflow that respects a 3% day, using the same figures the platform enforces, and points you to the free calculators that do the arithmetic for you.
Start with the two floors, not the leverage slider
Every sold MyFundedPerps challenge is a 1-Step evaluation with these risk rules, all measured from the starting balance, never current equity:
On a $100,000 account, the daily allowance is $3,000, measured from start-of-day equity including open-position profit or loss. If your start-of-day equity is $102,000, that day's loss floor sits at $99,000. The static max loss floor is starting balance minus the drawdown allowance: $97,000 on Select, $95,000 on Prime, $94,000 on Signature for a $100K size. Neither floor trails your highs. The daily loss limit resets at midnight New York time (04:00 UTC during EDT, 05:00 UTC during EST), and a reset never reopens a failed account or moves the max loss floor.
Two consequences matter for sizing:
- Loss rules use equity, including floating P/L. An open position that dips through a floor fails the account even if you planned to hold.
- Commissions and hourly swap fees debit your balance directly, eating the same headroom as a losing trade.
The position sizing funded account formula
The platform's Position Size Calculator works back from a risk budget and a stop distance, and that is exactly the right mental model. The formula:
Position size = dollar risk budget / distance between entry and stop
So the real decision is the risk budget per trade. A practical framework for a $100K account with a $3,000 daily allowance:
- Decide how many full-loss trades you will tolerate in one day. Many evaluation traders pick two or three. At three, your per-trade risk budget is $1,000.
- Measure your stop distance in price terms from your setup, not the other way around.
- Divide. With a $1,000 budget and a stop 0.5% away on a crypto perp, your position is about $200,000 of notional. With a stop 2% away, it is $50,000.
- Subtract friction. Crypto commission is 0.03% per fill, entry and exit. Scale that to your size and deduct it from the budget before you divide, not after.
Notice what is missing from this math: leverage. Leverage only determines whether the position fits your collateral and the market's cap. A $200,000 notional position on BTC at 10x max leverage needs $20,000 of margin, which a $100K account covers easily. The leverage figure (BTC and ETH at 10x with $1,000,000 exposure caps, as of launch day, September 2026; figures may have changed since) is a ceiling, not a target.
Use the calculators, but know their limits
MyFundedPerps publishes free tools at myfundedperpetuals.com/tools, and the docs are blunt about what they are:
The calculators do not read your account balance. The dashboard's enforced loss floors are the reference that matters, and the selected challenge's order summary is the reference for your actual terms. Treat every calculator output as a scenario, not a permission slip.
Three sizing habits that survive a 3% day
Size to the floor, not the balance. Because the static drawdown never trails, a $100K Select account that grows to $104,000 still has only $7,000 of total room above the $97,000 max loss floor. Growing equity adds buffer; it does not change the floor. On the first funded withdrawal, the floor locks permanently to the starting balance, so a $100K Signature that withdraws ends up with its floor at $100,000 and only its leftover profit as buffer. Requesting the maximum leaves a $0 buffer and closes the account.
Budget the day, then the trade. The daily floor is measured from start-of-day equity including open P/L. If yesterday closed strong, your floor is higher, but your dollar allowance is still 3% of starting balance. Traders who risk $3,000 per trade on a $100K account are one bad fill from a failed day. Traders who risk $500 to $1,000 per trade can be wrong repeatedly and stay alive.
Count the holding costs. Swap fees charge both longs and shorts hourly on the UTC hour boundary: 0.03% per day on crypto, 0.015% on stocks, commodities, and indices, 0.005% on forex, priced on notional at the boundary mark. A $200,000 crypto position held 24 hours pays about $60, straight out of the balance your loss floors measure.
A worked example on a $100K Prime
Start-of-day equity: $100,000. Daily floor: $97,000. Max loss floor: $95,000.
You want to long a crypto perp with a stop 1% below entry. Per-trade risk budget: $1,000 (one third of the daily allowance). Position size: $1,000 / 0.01 = $100,000 notional. Commission on the round trip at 0.03% per fill: about $60. Adjusted budget: your true worst case is roughly $1,060 plus slippage. A stop price is not a guaranteed execution price, so leave margin for that. Run the same numbers through the Position Size Calculator and the Drawdown Breach Calculator before the session, and check the dashboard floors before the order, not after.
Frequently asked questions
How much should I risk per trade on a funded account?
There is no platform rule setting a per-trade risk cap. The binding constraints are the 3% daily loss limit and the static max drawdown, both on starting balance. Many traders cap single-trade risk at a fraction of the daily allowance so several losing trades cannot end the account in one session.
Does higher leverage change my risk?
Leverage changes required margin and how close liquidation sits, but it does not change the dollar loss a position produces per point of adverse movement. A $100,000 notional position loses $1,000 on a 1% move whether you used 2x or 10x. The loss floors measure equity, so size from notional and stop distance, not from the leverage slider. Leverage and cap figures cited here are as of launch day, September 2026, and may have changed since.
Where do I check my remaining room before trading?
The dashboard shows both loss floors for the account, and those enforced values are the reference. The Drawdown Breach Calculator can model hypothetical scenarios, but it does not reproduce every account rule or the permanent loss-floor lock after a funded withdrawal.
Do fees count against the daily loss limit?
Yes. Commissions are charged per fill on entry and exit, and hourly swap fees debit the balance directly while a position is open. Both reduce the same equity that the daily loss and max loss rules measure.
Can I pass the evaluation with one large position?
The rules do not forbid it: there is no consistency rule and no minimum trading-day count. But the prohibited-activity policy covers evaluation gambling, meaning repeated maximum-risk attempts that treat challenge fees like lottery tickets. Sizing that respects the 3% day is both safer and clearly within the spirit of the evaluation.